Universal Serial Bus (USB) Type-C connectors complying with the USB 3.1 standard were developed soon after the standard was published in 2014. Unlike the conventional USB connectors, which must be used in the “correct” orientation and therefore often inconvenience the users by having to be inserted for a second time, USB Type-C connectors feature a “lack of directionality”, meaning they can be inserted with either side up and thus provide enhanced convenience of use. Another major feature of USB Type-C connectors is “slimness”, with a size of about 3×2.5 mm, which makes such connectors more suitable for use in the increasingly downsized computation devices than are their bulkier counterparts.
USB Type-C connectors, however, are not the only connectors in compliance with the USB 3.1 standard. As with the USB 2.0 standard, connectors conforming to the USB 3.1 standard also include USB Type-A connectors and Micro-B connectors. USB Type-A connectors are the standard USB interface and are generally used in personal computers. Micro-B connectors, on the other hand, are a USB interface designed for mobile devices and are typically used in smartphones (e.g., mobile phones operating on an Android operating system). In other words, USB Type-C, as well as USB Type-A and Micro-B, connectors allow consumers to enjoy high-speed data transmission enabled by the USB 3.1 standard.
As stated above, different types of electronic devices use connectors of different specifications. Therefore, when it is desired to connect electronic devices whose connectors are unalike, e.g., to connect a Nokia N1 tablet computer, which is mounted with a USB Type-C connector, to a personal computer with a USB Type-A connector, it is common practice to make the connection via an additional transmission cable that allows the tablet computer and the personal computer to transmit data to each other. As another example, an Apple MacBook laptop computer, which has a USB Type-C connector, and a smartphone with a Micro-B connector can be connected by a transmission cable so that data transmission between the laptop and the smartphone can be carried out.
Generally, the foregoing transmission cables have a USB Type-C connecter at one end and a USB Type-A or Micro-B connector at the other end, depending on production requirements. In order for an electronic device to identify the type of a transmission cable, i.e., a “USB Type-C to USB Type-A” transmission cable, which adapts a USB Type-C connector to a USB Type-A connector, or a “USB Type-C to Micro-B” transmission cable, which adapts a USB Type-C connector to a Micro-B connector, the USB 3.1 standard provides that each USB Type-C connector have a configuration channel (CC); that when a transmission cable has a USB Type-C connector and a USB Type-A connector at its two ends respectively, a resistor be connected between the configuration channel and a power terminal (Vbus) of the USB Type-C connector; and that when a transmission cable has a USB Type-C connector and a Micro-B connector at its two ends respectively, a resistor be connected between the configuration channel and a ground terminal (GND) of the USB Type-C connector. To meet this requirement, the pin of a configuration channel (CC) is typically designed to be adjacent to the pin of either a power terminal (Vbus), as shown in FIG. 1A, or a ground terminal (GND), as shown in FIG. 1B. That is to say, once a USB Type-C connector is produced, the type of connector to which it can adapt, i.e., the type of connector that can be used in the same transmission cable as itself, is fixed. For example, a USB Type-C connector designed to adapt to a USB Type-A connector cannot be used to adapt to a Micro-B connector. The above limitation causes trouble to connector and transmission cable manufacturers in terms of production and stock control.
According to the above, the structure of the USB Type-C connector on a transmission cable needs improvement, and in the light of this, the issue to be addressed by the present invention is to design a novel connector structure that meets the adaptation and transmission requirements of USB Type-C connectors.